Dual metal torque transmitting apparatuses and methods for making the same

Abstract

Apparatuses and methods are provided for transmitting torque in a way that can prolong the life of such apparatuses by using dissimilar materials for a body region and a torque transmitting region that absorbs the wear of the apparatuses, the apparatuses being constructed by methods of powder metallurgy. A torque transmitting apparatus can be provided and can include an annular body member composed of a first material and an outer ring member composed of a second powder metal material. The outer ring member can shrink about the annular body member during a sintering phase to form a single body in which the outer ring member can be fixedly attached to the annular body member.

1 . A torque transmitting apparatus comprising:
 a body member having an outer rim;   an outer member adjacent to and substantially surrounding the outer rim of the body member, the outer member constructed from a powder metal material shrunk onto the body member to fixedly engage the body member.   
     
     
         2 . The torque transmitting apparatus of  claim 1  wherein the body member is substantially annular. 
     
     
         3 . The torque transmitting apparatus of  claim 1  wherein the outer member is substantially annular. 
     
     
         4 . The torque transmitting apparatus of  claim 1  wherein the body member is constructed from a second powder metal material. 
     
     
         5 . The torque transmitting apparatus of  claim 4  wherein the second powder metal material is iron or iron alloy. 
     
     
         6 . The torque transmitting apparatus of  claim 1  wherein the powder metal material is bronze or copper alloy. 
     
     
         7 . The torque transmitting apparatus of  claim 1  wherein the apparatus is a gear. 
     
     
         8 . The torque transmitting apparatus of  claim 1  wherein the outer member is configured to have a teeth portion. 
     
     
         9 . A method for making a torque transmitting apparatus comprising:
 compacting a first powder metal material into a first green compact being substantially annular;   compacting a second powder metal material into a second green compact being substantially annular;   heating the second green compact at a first temperature to sinter the second green compact to form an annular body member;   positioning the first green compact about the annular body member; and   heating the first green compact and annular body together at a second temperature such that the substantially annular first green compact is sintered, whereby the first green compact shrinks around the annular body member.   
     
     
         10 . The method according to  claim 9  wherein the first powder metal material is bronze or copper alloy. 
     
     
         11 . The method according to  claim 9  wherein the second powder metal material is iron or iron alloy. 
     
     
         12 . The method according to  claim 9  wherein the first green compact is configured to have a tooth portion about its circumference. 
     
     
         13 . A method for making a torque transmitting apparatus comprising:
 positioning a powder metal outer member substantially about a body member; and   heating the powder metal outer member and body member such that the powder metal outer member is sintered, whereby the powder metal outer member shrinks about the body member to fixedly engage the body member.   
     
     
         14 . The method according to  claim 13  wherein the powder metal outer member is bronze or copper alloy. 
     
     
         15 . The method according to  claim 13  wherein the body member is constructed from a second powder metal material. 
     
     
         16 . The method according to  claim 15  wherein the second powder metal material is iron or iron alloy. 
     
     
         17 . A torque transmitting apparatus made by the steps of:
 providing a body member;   positioning an outer member about the body member; and   heating the outer member and body member together such that the outer member undergoes a sintering process and thereby shrinks around the body member.   
     
     
         18 . The apparatus of  claim 17  wherein the apparatus is a gear. 
     
     
         19 . The apparatus of  claim 17  wherein the body member is iron or iron alloy. 
     
     
         20 . The apparatus of  claim 19  wherein the outer member is bronze or copper alloy powder metal material.